This paper contributes to the foundations of a theory of rational choice for artiﬁcial agents in dynamic environments. Our work is developed within a theoretical framework, originally due to Bratman, that models resource-bounded agents as operating against the background of some current set of intentions, which helps to frame their subsequent reasoning. In contrast to the standard theory of rational choice, where options are evaluated in isolation, we therefore provide an analysis of situations in which the options presented to an (...) agent are evaluated against a background context provided by the agent’s current plans—commitments to future activities, which may themselves be only partially speciﬁed. The interactions between the new options and the background context can complicate the task of evaluating the option, rendering it either more or less desirable in context than it would have been in isolation. 2001 Elsevier Science B.V. All rights reserved. (shrink)
This paper explores principles governing the rational balance among an agent's beliefs, goals, actions, and intentions. Such principles provide specifications for artificial agents, and approximate a theory of human action (as philosophers use the term). By making explicit the conditions under which an agent can drop his goals, i.e., by specifying how the agent is committed to his goals, the formalism captures a number of important properties of intention. Specifically, the formalism provides analyses for Bratman's three characteristic functional roles played (...) by intentions [7, 9], and shows how agents can avoid intending all the foreseen side-effects of what they actually intend. Finally, the analysis shows how intentions can be adopted relative to a background of relevant beliefs and other intentions or goals. By relativizing one agent's intentions in terms of beliefs about another agent's intentions (or beliefs'), we derive a preliminary account of interpersonal commitments. (shrink)
Since the 1930s, scientists studying the neurological disease scrapie had assumed that the infectious agent was a virus. By the mid 1960s, however, several unconventional properties had arisen that were difficult to reconcile with the standard viral model. Evidence for nucleic acid within the pathogen was lacking, and some researchers considered the possibility that the infectious agent consisted solely of protein. In 1982, Stanley Prusiner coined the term `prion' to emphasize the agent's proteinaceous nature. This infectious protein hypothesis was denounced (...) by many scientists as `heretical'.This two-part essay asks why the concept of an infectious protein was considered controversial. Some biologists justified their evaluation of this hypothesis on the grounds that an infectious protein contradicted the `central dogma of molecular biology'. Others referred to vague theoretical constraints such as molecular biology's `theoretical structure' or `framework'. Examination of the objections raised by researchers reveals exactly what generalizations were being challenged by a protein model of infection.This two-part survey of scrapie and prion research reaches several conclusions: A theoretical framework is present in molecular biology, exerting its influence in hypothesis formation and evaluation; This framework consists of several related, yet separable, generalizations or `elements', including Francis Crick's Central Dogma and Sequence Hypothesis, plus notions concerning infection, replication, protein synthesis, and protein folding; The term `central dogma' has stretched beyond Crick's original 1958 definition to encompass at least two other `framework elements': replication and protein synthesis; and From the study of scrapie and related diseases, biological information has been delineated into at least two classes: sequential and what I call `conformational'.In Part I of this essay, a brief review of the central dogma was given, and the developments in scrapie research from 1965 to 1972 were traced. This section summarized many of the puzzling, non-virus-like properties of the scrapie agent. Alternative hypotheses to the viral explanation were presented, including early versions of a protein-only hypothesis. Part II of this essay will follow the developments in scrapie and prion research from the mid-1970s through 1991. The growing prominence of a protein-only model of infection will be countered by continued objections from many researchers to a pathogen devoid of nucleic acid. These objections will help illuminate those generalizations in molecular biology that were indeed challenged by a protein-only model of infection. (shrink)
The “Perky effect” is the interference of visual imagery with vision. Studies of this effect show that visual imagery has more than symbolic properties, but these properties differ both spatially (including “pictorially”) and temporally from those of vision. We therefore reject both the literal picture-in-the-head view and the entirely symbolic view.
There is an abundant and growing feminist literature examining the implications of reproductive technologies that separate genetic, physiological, and social motherhood. The literature explains the development of these technologies in terms of the motivations of men, stressing the victimization of women by the medical and legal institutions and the commodification of these technologies. This article examines these technologies from a Marxist-Feminist perspective, locating their sources in the overall development of the forces of production; that is, in structural changes irreducible to (...) their microfoundations. In the process of changing the biological conditions of intergenerational social reproduction, these technologies have established the material basis for the structural separation between the mode of procreation and the mode of social and physical reproduction. These structural changes are generating new identities and forms of consciousness that clash with taken-for-granted ideas about motherhood. These differences are captured in feminist debates about the significance of these technologies. (shrink)
The developing infant can accomplish all important perceptual tasks that an adult can, albeit with less skill or precision. Through infant perception research, infant responses to experiences enable researchers to reveal perceptual competence, test hypotheses about processes, and infer neural mechanisms, and researchers are able to address age-old questions about perception and the origins of knowledge.In Development of Perception in Infancy: The Cradle of Knowledge Revisited, Martha E. Arterberry and Philip J. Kellman study the methods and data of scientific (...) research on infant perception, introducing and analyzing topics through philosophical, theoretical, and historical contexts. Infant perception research is placed in a philosophical context by addressing the abilities with which humans appear to be born, those that appear to emerge due to experience, and the interaction of the two. The theoretical perspective is informed by the ecological tradition, and from such a perspective the authors focus on the information available for perception, when it is used by the developing infant, the fit between infant capabilities and environmental demands, and the role of perceptual learning. Since the original publication of this book in 1998, Arterberry and Kellman address in addition the mechanisms of change, placing the basic capacities of infants at different ages and exploring what it is that infants do with this information. Significantly, the authors feature the perceptual underpinnings of social and cognitive development, and consider two examples of atypical development - congenital cataracts and Autism Spectrum Disorder. Professionals and students alike will find this book a critical resource to understanding perception, cognitive development, social development, infancy, and developmental cognitive neuroscience, as research on the origins of perception has changed forever our conceptions of how human mental life begins. (shrink)
Developmental research on infants' categorization of living and nonliving objects finds that very young children are equally skilled in grouping such objects. The lack of a specialization for one type of object over another may be due to knowledge of function and the time frame for acquiring such knowledge.
Meditation is an umbrella term for a number of mental training practices designed to improve the monitoring and regulation of attention and emotion. Some forms of meditation are now being used for clinical intervention. To accompany the increased clinical interest in meditation, research investigating the neural basis of these practices is needed. A central hypothesis of contemplative neuroscience is that meditative states, which are unique on a phenomenological level, differ on a neurophysiological level. To identify the electrophysiological correlates of meditation (...) practice, the electrical brain activity of highly skilled meditators engaging in one of six meditation styles was recorded. A mind-wandering task served as a control. Lempel–Ziv complexity showed differences in nonlinear brain dynamics during meditation compared with mind wandering, suggesting that meditation, regardless of practice, affects neural complexity. In contrast, there were no differences in power spectra at six different frequency bands, likely due to the fact that participants engaged in different meditation practices. Finally, exploratory analyses suggest neurological differences among meditation practices. These findings highlight the importance of studying the electroencephalography correlates of different meditative practices. (shrink)
A common practice in textbooks is to introduce concepts or strategies in association with specific people. This practice aligns with research suggesting that using “real-world” contexts in textbooks increases students’ motivation and engagement. However, other research suggests this practice may interfere with transfer by distracting students or leading them to tie new knowledge too closely to the original learning context. The current study investigates the effects on learning and transfer of connecting mathematics strategies to specific people. A total of 180 (...) college students were presented with an example of a problem-solving strategy that was either linked with a specific person or presented without a person. Students who saw the example without a person were more likely to correctly transfer the novel strategy to new problems than students who saw the example presented with a person. These findings are the first evidence that using people to present new strategies is harmful for learning and transfer. (shrink)
Are there parallels between the "moment of insight" in science and the emergence of the "unknowable" in religious faith? Where does scientific insight come from? Award-winning biologist Robert Pollack argues that an alliance between religious faith and science is not necessarily an argument in favor of irrationality: the two can inform each other's visions of the world. Pollack begins by reflecting on the large questions of meaning and purpose--and the difficulty of finding either in the orderly world described (...) by the data of science. He considers the obligation to find meaning and purpose despite natural selection's claim to be a complete explanation of our presence as a species--a claim that calls upon neither natural intention, nor design, nor Designer. Next, the book focuses on matters of free will, from the choice of a scientist to accept evidence, to the choice of a religious person to accept a revelation, to a patient's loss of free will in medical treatment. Here Pollack addresses questions of ethics and offers a provocative comparison of two difficult texts whose contents remain incompletely understood: the DNA "text" of the human genome and the Hebrew record of Jewish written and oral law. In closing, Pollack considers the promise of genetic medicine in enabling us to glimpse our own future and offers a reconsideration of the possible utility of the so-called placebo effect in curing illness. Whether refuting a DNA-based biological model of Judaism or discussing the Darwinian concept of the species, Pollack, under the banner of free inquiry, presents a genuine, vital, and well-argued assay of the intersection of science and religion. (shrink)